Rosin esters and compositions thereof

ABSTRACT

Rosin esters are provided. The rosin esters can exhibit improved color (e.g., the rosin ester can have a neat Gardner color of 4 or less), improved oxidative stability (e.g., when 1000 ppm or less of an antioxidant is present in combination with the rosin ester, the rosin ester can exhibit an oxidative-induction time at 130° C. of at least 30 minutes), improved color stability (e.g., the rosin ester can retain a neat Gardner color of 5 or less when heated to a temperature of 160° C. for a period of three hours), or combinations thereof. Also provided polymeric compositions comprising the rosin esters, as well as methods of making the rosin esters.

TECHNICAL FIELD

This application relates generally to rosin esters, as well as methodsof making and using thereof.

BACKGROUND

Rosin esters, including rosin esters derived from polyhydric alcohols,have been known for more than 50 years. See, for example, U.S. Pat. No.1,820,265 to Bent, et al. Rosin esters are typically formed by thereaction of rosin. Which is primarily a mixture of isomeric C₂₀tricyclic mono-carboxylic acids known as rosin acids, with alcohols suchas glycerol or pentaerythritol. The resultant rosin esters serve asadditives in a variety of applications, including as tackifiers inhot-melt and pressure-sensitive adhesives, modifiers for rubbers andvarious plastics, emulsifiers for synthetic rubbers, base materials forchewing gum, resins in coating compositions such as traffic paints andinks, and sizing agents for paper making.

While suitable for many applications, many existing rosin esters fail topossess suitable properties for particular applications. Notably, manycommercially available rosin esters are colored (e.g., yellow oryellowish brown) and exhibit poor stability. Accordingly, therecontinues to be a need for rosin esters which exhibit improved color(e.g., are colorless or nearly colorless) and improved stability.

SUMMARY

Provided herein are rosin esters that include at least 70% by weight ofan esterified dehydroabietic acid and an esterified dihydroabietic acid.The weight ratio of the esterified dehydroabietic acid to the esterifieddihydroabietic acid in the rosin ester can range from 1.3:1 to 1:2.6(e.g., from 1.3:1 to 1:2.5, from 1.3:1 to 1:1.6, or from 1.2:1 to1:1.5). The rosin esters can be derived from tall oil rosin, gum rosin,wood rosin, or a combination thereof. In some cases, the rosin ester isalso derived from a polyhydric alcohol, such as a polyhydric alcoholselected from the group consisting of ethylene glycol, propylene glycol,diethylene glycol, triethylene glycol, tetraethylene glycol,trimethylene glycol, glycerol, trimethylolpropane, trimethylolethane,pentaerythritol, mannitol, and combinations thereof.

The rosin esters can be colorless or nearly colorless. For example, therosin ester can have a neat Gardner color of 4 or less (e.g., 1.5 orless, or 1 or less). The rosin esters can have improved color stability(e.g., the rosin ester can retain a neat Gardner color of 5 or less whenheated to a temperature of 160° C. for a period of three hours). Therosin esters can also exhibit improved oxidative stability (e.g., when1000 ppm or less of an antioxidant is present in combination with therosin ester, the rosin ester can exhibit an oxidative-induction time at130° C. of at least 30 minutes).

Also provided are polymeric compositions comprising a polymer derivedfrom one or more ethylenically-unsaturated monomers, or a blend of twoor more such polymers, and a rosin ester. The polymer can be ahomopolymer or a copolymer (e.g., a random copolymer or a blockcopolymer) derived from one or more ethylenically-unsaturated monomers,such as (meth)acrylate monomers, vinyl aromatic monomers (e.g.,styrene), vinyl esters of carboxylic acids, (meth)acrylonitriles, vinylhalides, vinyl ethers, (meth)acrylamides and (meth)acrylamidederivatives, ethylenically unsaturated aliphatic monomers (e.g.,ethylene, butylene, butadiene), and combinations thereof. In someembodiments, the rosin ester includes more than one type of rosin ester.

In some embodiments, the polymer derived from one or moreethylenically-unsaturated monomers comprises a copolymer of ethylene andn-butyl acrylate. In some embodiments, the polymer derived from one ormore ethylenically-unsaturated monomers comprises a copolymer of styreneand one or more of isoprene and butadiene. In certain embodiments, thepolymer derived from one or more ethylenically-unsaturated monomerscomprises a polymer derived from vinyl acetate. Polymers derived fromvinyl acetate include polymers derived, at least in part, frompolymerization of vinyl acetate monomers. For example, the polymerderived from vinyl acetate can be a homopolymer of vinyl acetate (i.e.,polyvinyl acetate; PVA). The polymer derived from vinyl acetate can alsobe a copolymer of vinyl acetate and one or more additionalethylenically-unsaturated monomers (e.g., poly(ethylene-co-vinylacetate), EVA). In certain embodiments, the composition is a hot-meltadhesive, such as an EVA-based hot-melt adhesive.

In some embodiments, the polymer is present in the composition in anamount ranging from 20% to 60% by weight, based on the total weight ofthe composition (e.g., from 30% to 40% by weight). In some embodiments,the rosin ester is present in the composition in an amount ranging from20% to 50% by weight, based on the total weight of the composition from30% to 40% by weight). In certain embodiments, the weight ratio of thepolymer to the total amount of esterified dehydroabietic acid andesterified dihydroabietic acid in the composition is from 1:2.2 to 4.3:1(e.g., from 1:1.1 to 2:1).

The polymeric compositions can exhibit improved thermal stability,including improved viscosity stability on aging at elevated temperatures(thermal aging), improved color stability on thermal aging, orcombinations thereof. For example, in some embodiments, the compositionexhibits a change in viscosity of less than 5% when heated to atemperature of 177° C. for a period of 96 hours. In some cases, thecomposition exhibits a change of 5 or less Gardner color units whenheated to a temperature of 177° C. for a period of 96 hours.

Also provided are methods of making rosin esters. Methods of makingrosin esters can comprise (a) esterifying as rosin with an alcohol toprovide a crude rosin ester, and (b) hydrogenating the crude rosin esterto form the rosin ester.

Esterification step (a) can comprise contacting a rosin with a suitablealcohol under suitable conditions to provide the crude rosin ester. Therosin can be selected from the group consisting of tall oil rosins, gumrosins, wood rosins, or combinations thereof. In some embodiments, thealcohol comprises a polyhydric alcohol, such as ethylene glycol,propylene glycol, diethylene glycol, triethylene glycol, tetraethyleneglycol, trimethylene glycol, glycerol, trimethylolpropane,trimethylolethane, pentaerythritol, dipentaerythritol, mannitol, andcombinations thereof. Hydrogenation step (b) can comprise contacting thecrude rosin ester with a hydrogenation catalyst. Step (b) can beperformed at an elevated temperature, an elevated pressure, orcombinations thereof.

Optionally, a solvent can be present in esterification step (a),hydrogenation step (b), or combinations thereof. In certain embodiments,the rosin esterified in step (a) and/or the crude rosin esterhydrogenated in step (b) comprise less than 25% by weight solvent. Insome embodiments, the concentration of esterified rosin acids in thecrude rosin ester hydrogenated in step (b) is 75% or more by weight,based on the total weight of the crude rosin ester. In some embodiments,the crude rosin ester is substantially free of solvent (e.g., the cruderosin ester comprises less than 1% by weight solvent, based on the totalweight of the crude rosin ester). In certain embodiments, the cruderosin ester hydrogenated in step (b) has a viscosity of 1,000 cP or lessat 25° C.

In some embodiments, the crude rosin ester obtained from esterificationstep (a) is hydrogenated in step (b) without an intervening distillationstep. In certain embodiments, the crude rosin ester obtained fromesterification step (a) is hydrogenated in step (b) without anyintervening purification step.

In some cases, methods of making the rosin esters described hereininclude only a single hydrogenation step. In some embodiments, methodsof making the rosin esters described herein consist essentially ofesterifying step (a) and hydrogenating step (b). In certain embodiments,methods of making the rosin esters described herein consist ofesterifying step (a) and hydrogenating step (b).

In certain embodiments, methods of making rosin esters can furthercomprise disproportionating the rosin prior to the esterifying step (a).The step of disproportionating the rosin can comprise contacting therosin with a disproportionation catalyst, such as a phenol sulfide-typedisproportionation catalyst.

DETAILED DESCRIPTION

Provided herein are rosin esters. The rosin esters can exhibit improvedcolor (e.g., the rosin ester can have a neat Gardner color of 4 orless), improved oxidative stability (e.g., when 1000 ppm or less of anantioxidant is present in combination with the rosin ester, the rosinester can exhibit an oxidative-induction time at 130° C. of at least 30minutes), improved color stability (e.g., the rosin ester can retain aneat Gardner color of 5 or less when heated to a temperature of 160° C.for a period of three hours), or combinations thereof.

Rosin esters can be formed by the esterification of rosin. Rosin, alsocalled colophony or Greek pitch (Pix grœca), is a solid hydrocarbonsecretion of plants, typically of conifers such as pines (e.g., Pinuspalustris and Pinus caribaea). Rosin can include a mixture of rosinacids, with the precise composition of the rosin varying depending inpart on the plant species. Rosin acids are C₂₀ fused-ring monocarboxylicacids with a nucleus of three fused six-carbon rings containing doublebonds that vary in number and location. Examples of rosin acids includeabietic acid, neoabietic acid, dehydroabietic acid, dihydroabietic acid,pimaric acid, levopimaric acid, sandaracopimaric acid, isopimaric acid,and palustric acid. Natural rosin typically consists of a mixture ofseven or eight resin acids, in combination with minor amounts of othercomponents.

Rosin is commercially available, and can be obtained from pine trees bydistillation of oleoresin (gum rosin being the residue of distillation),by extraction of pine stumps (wood rosin) or by fractionation of talloil (tall oil rosin). Any type of rosin can be used to prepare the rosinesters described herein, including tall oil rosin, gum rosin and woodrosin and mixtures thereof. In certain embodiments, the rosin ester isderived from tall oil rosin. Examples of commercially available rosinsinclude tall oil rosins such as SYLVAROS® 90, commercially availablefrom Arizona Chemical.

As described above, rosin includes a mixture of rosin acids (e.g.,abietadienoic acids) which can include conjugated double bonds withintheir ring systems. These conjugated double bonds can be a source ofoxidative instability. Accordingly, in some cases, the rosin, rosinester, or combinations thereof are processed to decrease the weightpercent of components which include conjugated double bonds. Forexample, the PAN number of rosin or a rosin ester refers to the weightpercentage of abietadienoic acids (in particular palustric, abietic andneoabietic acids) present in the rosin or rosin ester, based on thetotal weight of the rosin or rosin ester. The term “PAN number”, as usedherein, specifically refers to the sum of the weight percentages ofpalustric, abietic and neoabietic acid moieties in a rosin or rosinester, as determined according to method described in ASTM D5974-00(2010).

The rosin ester can have a low PAN number. In some embodiments, therosin ester can have a PAN number, as determined according to the methoddescribed in ASTM D5974-00 (2010), of 15.0 or less (e.g., 14.5 or less,14.0 or less, 13.5 or less, 13.0 or less, 12.5 or less, 12.0 or less,11.5 or less, 11.0 or less, 10.5 or less, 10.0 or less, 9.5 or less, 9.0or less, 8.5 or less, 8.0 or less, 7.5 or less, 7.0 or less, 6.5 orless, 6.0 or less, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less,3.5 or less, 3.0 or less, 2.5 or less, 2.0 or less, 1.5 or less, or 1.0or less).

The rosin ester can comprise at least 70% by weight of an esterifieddehydroabietic acid and an esterified dihydroabietic acid, based on thetotal weight of the rosin ester (e.g., at least 75% by weight of anesterified dehydroabietic acid and an esterified dihydroabietic acid, atleast 80% by weight of an esterified dehydroabietic acid and anesterified dihydroabietic acid, at least 85% by weight of an esterifieddehydroabietic acid and an esterified dihydroabietic acid, at least 90%by weight of an esterified dehydroabietic acid and an esterifieddihydroabietic acid, or at least 95% by weight of an esterifieddehydroabietic acid and an esterified dihydroabietic acid).

In some embodiments, the weight ratio of esterified dehydroabietic acidto esterified. dihydroabietic acid in the rosin ester is 1.3:1 or less(e.g., 1.25:1 or less, 1.2:1 or less, 1.15:1 or less, 1.1:1 or less,1.05:1 or less, 1:1 or less, 1:1.05 or less, 1:1.1 or less, 1:1.15 orless, 1:1.2 or less, 1:1.25 or less, 1:1.3 or less, 1:1.35 or less,1:1.4 or less, 1:1.45 or less, 1:1.5 or less, 1:1.55 or less, 1:1.6 orless, 1:1.65 or less, 1:1.7 or less, 1:1.75 or less, 1:1.8 or less,1:1.85 or less, 1:1.9 or less, 1:1.95 or less, 1:2 or less, 1:2.05 orless, 1:2.1 or less, 1:2.15 or less, 1:2.2 or less, 1:2.25 or less,1:2.3 or less, 1:2.35 or less, 1:2.4 or less; 1:2.45 or less, 1:2.5 orless, or 1:2.55). In some embodiments, the weight ratio of esterifieddehydroabietic acid to esterified dihydroabietic acid in the rosin esteris at least 1:2.6 (e.g., at least 1:2.55, at least 1:2.5, at least1:2.45, at least 1:2.4, at least 1:2.35, at least 1:2.3, at least1:2.25, at least 1:2.2, at least 1:2.15, at least 1:2.1, at least1:2.05, at least 1:2, at least 1:1.95, at least 1:1.9, at least 1:4.85,at least 1:1.8, at least 1:1.75, at least 1:1.7, at least 1:1.65, atleast 1:1.6, at least 1:1.55, at least 1:1.5, at least 1:1.45, at least1:1.4, at least 1:1.35, at least 1:1.3, at least 1:1.25, at least 1:1.2,at least 1:1.15, at least 1:1, at least 1:1.05, at least 1:1, at least1.05:1, at least 1.1:1, at least 1.15:1, at least 1.2:1, or at least1.25:1).

The weight ratio of esterified dehydroabietic acid to esterifieddihydroabietic acid in the rosin ester can range from any of the minimumvalues described above to any of the maximum values described above. Forexample, the weight ratio of esterified dehydroabietic acid toesterified dihydroabietic acid in the rosin ester can range from 1.3:1to 1:2.6 (e.g., from 1.3:1 to 1:2.5, from 1.3:1 to 1:1.6, or from 1.2:1to 1:1.5).

The rosin ester can be derived from any suitable alcohol, includemonoalcohols, diols, and other polyols. Examples of suitable alcoholsinclude glycerol, pentaerythritol, dipentaerythritol, ethylene glycol,diethylene glycol, triethylene glycol, sorbitol, neopentylglycol,trimethylolpropane, methanol, ethanol, propanol, butanol, amyl alcohol,2-ethyl hexanol, diglycerol, tripentaerythritol, C₈-C₁₁ branched orunbranched alkyl alcohols, and C₇-C₁₆ branched or unbranchedarylalkylalcohols. In certain embodiments, the rosin ester is derivedfrom a polyhydric alcohol. In certain embodiments, the polyhydricalcohol can be selected from the group consisting of ethylene glycol,propylene glycol, diethylene glycol, triethylene glycol, tetraethyleneglycol, trimethylene glycol, glycerol, trimethylolpropane,trimethylolethane, pentaerythritol, dipentaerythritol, mannitol, andcombinations thereof.

The rosin ester can have a weight average molecular weight, asdetermined using gel permeation chromatography (GPC) as described inASTM D5296-05, of at least 800 g/mol (e.g., at least 850 g/mol, at least900 g/mol, at least 950 g/mol, at least 1000 g/mol, at least 1050 g/mol,at least 1100 g/mol, at least 1150 g/mol, at least 1200 g/mol, at least1250 g/mol, at least 1300 g/mol, at least 1350 g/mol, at least 1400g/mol, at least 1450 g/mol, at least 1500 g/mol, at least 1550 g/mol, atleast 1600 g/mol, at least 1650 g/mol, at least 1700 g/mol, at least1750 g/mol, at least 1800 g/mol, at least 1850 g/mol, at least 1900g/mol, or at least 1950 g/mol). The blend of rosin esters can have aweight average molecular weight of 2000 g/mol or less (e.g., 1950 g/molor less, 1900 g/mol or less, 1850 g/mol or less, 1800 g/mol or less,1750 g/mol or less, 1700 g/mol or less, 1650 g/mol or less, 1600 g/molor less, 1550 g/mol or less, 1500 g/mol or less, 1450 g/mol or less,1400 g/mol or less, 1350 g/mol or less, 1300 g/mol or less, 1250 g/molor less, 1200 g/mol or less, 1150 g/mol or less, 1100 g/mol or less,1050 g/mol or less, 1000 g/mol or less, 950 g/mol or less, 900 g/mol orless, or 850 g/mol or less).

The rosin ester can have a weight average molecular weight ranging fromany of the minimum values above to any of the maximum values above. Forexample, the rosin ester can have a weight average molecular weight offrom 800 g/mol to 2000 g/mol (e.g., from 900 g/mol to 1600 g/mol, orfrom 1000 g/mol to 1500 g/mol).

The rosin esters can have a low neat Gardner color. In some embodiments,the rosin ester has a neat Gardner color, as determined according to themethod described in ASTM D1544-04 (2010), of 4.0 or less (e.g., 3.5 orless, 3.0 or less, 2.5 or less, 2.0 or less, 1.5 or less, 1.0 or less,or 0.5 or less).

In certain embodiments, the rosin esters can exhibit improved colorstability. For example, the ester can retain a neat Gardner color of 5or less (e.g., 4.5 or less, 4.0 or less, 3.5 or less, 3.0 or less, 2.5or less, 2.0 or less, 1.5 or less, 1.0 or less, or 0.5 or less) whenheated to a temperature of 160° C. for a period of three hours.

The rosin esters can also exhibit improved oxidative stability. Forexample, in some embodiments, when 1000 ppm or less of an antioxidant ispresent in combination with the rosin ester, the rosin ester can exhibitan oxidative-induction time at 130° C., as measured using the methodsspecified in ASTM D5483-05(2010), of at least 30 minutes (e.g., at least31 minutes, at least 32 minutes, at least 33 minutes, at least 34minutes, at least 35 minutes, at least 36 minutes, at least 37 minutes,at least 38 minutes, at least 39 minutes, at least 40 minutes, at least41 minutes, at least 42 minutes, at least 43 minutes, at least 44minutes, at least 45 minutes, at least 50 minutes, at least 55 minutes,at least 60 minutes, at least 65 minutes, at least 70 minutes, at least75 minutes, or longer). For example, when the rosin ester includes 1000ppm of antioxidant, or when the rosin ester includes less than 1000 ppmof antioxidant (e.g., 800 ppm of antioxidant, 600 ppm of antioxidant,400 ppm of antioxidant, 200 ppm of antioxidant, 100 ppm of antioxidant,50 ppm of antioxidant, or 0 ppm of antioxidant), the rosin ester canexhibit the oxidative-induction times described above at 130° C., asmeasured using the methods specified in ASTM D5483-05(2010). In somecases, when 1000 ppm or less of an antioxidant is present in combinationwith the rosin ester, the rosin ester can exhibit an oxidative-inductiontime at 130° C., as measured using the methods specified in ASTMD5483-05(2010), of 250 minutes or less (e.g., 200 minutes or less).

Optionally, the rosin esters can have a low hydroxyl number. In someembodiments, the rosin ester has a hydroxyl number, as measured using amodified version of the standard method provided in DIN 53240-2(different solvent tetrahydrofuran was applied), of 5.0 or less (e.g.,4.5 or less, 4.0 or less, 3.5 or less, 3.0 or less, 2.5 or less, 2.0 orless, 1.5 or less, or 1.0 or less). The hydroxyl number is expressed asmg KOH per gram rosin ester sample.

The rosin ester can have a low acid number. In some embodiments, therosin ester has an acid number, as determined according to the methoddescribed in ASTM D465-05 (2010), of 10.0 or less (e.g., 9.5 or less,9.0 or less, 8.5 or less, 8.0 or less, 7.5 or less, 7.0 or less, 6.5 orless, 6.0 or less, 5.5 or less, 5.0 or less, 4.5 or less, 4.0 or less,3.5 or less, 3.0 or less, 2.5 or less, 2.0 or less, 1.5 or less, or 1.0or less). The acid number is expressed as mg KOH per gram rosin estersample.

The rosin ester can optionally have low sulfur content. Sulfur contentcan be measured with an ANTEK® 9000 sulfur analyzer using the standardmethods described in ASTM D5453-05. In some embodiments, the rosin estercomprises less than 400 ppm sulfur (e.g., less than 350 ppm sulfur, lessthan 300 ppm sulfur, less than 250 ppm sulfur, or less than 200 ppmsulfur).

Also provided are polymeric compositions comprising a rosin esterdescribed herein and a polymer derived from one or moreethylenically-unsaturated monomers. In this context, a polymer derivedfrom an ethylenically-unsaturated monomer includes polymers derived, atleast in part, from polymerization of the ethylenically-unsaturatedmonomer. For example, a polymer derived from anethylenically-unsaturated monomers can be obtained by, for example,radical polymerization of a monomer mixture comprising theethylenically-unsaturated monomer. A polymer derived from anethylenically-unsaturated monomer can be said to contain monomer unitsobtained by polymerization (e.g., radical polymerization) of theethylenically-unsaturated monomer. Polymeric compositions can alsocomprise a rosin ester described herein and a blend of two or morepolymers derived from one or more ethylenically-unsaturated monomers. Inthese cases, the blend of two or more polymers can be, for example, ablend of two or more polymers having different chemical compositions(e.g., a blend of poly(ethylene-co-vinyl acetate) and polyvinyl acetate;or a blend of two poly(ethylene-co-vinyl acetates) derived fromdifferent weight percents of ethylene and vinyl acetate monomers).

In some embodiments, the rosin ester includes more than one type ofrosin ester. For example, the rosin ester can include a mixture of tworosin esters which are derived from the same type of rosin and twodifferent alcohols (e.g., a pentaerythritol ester of tall oil rosin anda glycerol ester of tall oil rosin), a mixture of two rosin esters whichare derived from the same alcohol and two different types of rosin(e.g., a pentaerythritol ester of tall oil rosin and a pentaerythritolester of gum rosin), or a mixture of two rosin esters which are derivedfrom two different alcohols and two different types of rosin (e.g., apentaerythritol ester of tall oil rosin and a glycerol ester of gumrosin).

The polymer can be a homopolymer or a copolymer (e.g., a randomcopolymer or a block copolymer) derived from one or moreethylenically-unsaturated monomers. In other words, the homopolymer orcopolymer can include monomer units of one or moreethylenically-unsaturated monomers. The polymer can be a branchedpolymer or copolymer. For example, polymer can be a graft copolymerhaving a polymeric backbone and a plurality of polymeric side chainsgrafted to the polymeric backbone. In some cases, the polymer can be agraft copolymer having a backbone of a first chemical composition and aplurality of polymeric side chains that are structurally distinct fromthe polymeric backbone (e.g., having a different chemical compositionthan the polymeric backbone) grafted to the polymeric backbone.

Examples of suitable ethylenically-unsaturated monomers include(meth)acrylate monomers, vinyl aromatic monomers (e.g., styrene), vinylesters of a carboxylic acids, (meth)acrylonitriles, vinyl halides, vinylethers, (meth)acrylamides and (meth)acrylamide derivatives,ethylenically unsaturated aliphatic monomers (e.g., ethylene, butylene,butadiene), and combinations thereof. As used herein, the term“(meth)acrylate monomer” includes acrylate, methacrylate, diacrylate,and dimethacrylate monomers. Similarly, the term “(meth)acrylonitrile”includes acrylonitrile, methacrylonitrile, etc. and the term“(meth)acrylamide” includes acrylamide, methacrylamide, etc.

Suitable (meth)acrylate monomers include esters of α,β-monoethylenicallyunsaturated monocarboxylic and dicarboxylic acids having 3 to 6 carbonatoms with alkanols having 1 to 20 carbon atoms (e.g., esters of acrylicacid, methacrylic acid, maleic acid, fumaric acid, or itaconic acid,with C₁-C₂₀, C₁-C₁₂, C₁-C₈, or C₁-C₄ alkanols). Exemplary (meth)acrylatemonomers include, but are not limited to, methyl acrylate, methyl(meth)acrylate, ethyl acrylate, ethyl (meth)acrylate, butyl acrylate,butyl (meth)acrylate, isobutyl (meth)acrylate, n-hexyl (meth)acrylate,ethylhexyl (meth)acrylate, n-heptyl (meth)acrylate, ethyl(meth)acrylate, 2-methylheptyl (meth)acrylate, octyl (meth)acrylate,isooctyl (meth)acrylate, n-nonyl (meth)acrylate, isononyl(meth)acrylate, n-decyl (meth)acrylate, isodecyl (meth)acrylate, dodecyl(meth)acrylate, lauryl (meth)acrylate, tridecyl (meth)acrylate, stearyl(meth)acrylate, glycidyl (meth)acrylate, alkyl crotonates, vinylacetate, di-n-butyl maleate, di-octylmaleate, acetoacetoxyethyl(meth)acrylate, acetoacetoxypropyl (meth)acrylate, hydroxyethyl(meth)acrylate, allyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate,cyclohexyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate, 2-methoxy(meth)acrylate, 2-(2-ethoxyethoxy)ethyl (meth)acrylate, 2-ethylhexyl(meth)acrylate, 2-propylheptyl (meth)acrylate, 2-phenoxyethyl(meth)acrylate, isobornyl (meth)acrylate, caprolactone (meth)acrylate,polypropyleneglycol mono(meth)acrylate, polyethyleneglycol(meth)acrylate, benzyl (meth)acrylate, 2,3-di(acetoacetoxy)propyl(meth)acrylate, hydroxypropyl (meth)acrylate, methylpolyglycol(meth)acrylate, 3,4-epoxycyclohexylmethyl (meth)acrylate, 1,6 hexanedioldi(meth)acrylate, 1,4 butanediol di(meth)acrylate and combinationsthereof.

Suitable vinyl aromatic compounds include styrene, α- andp-methylstyrene, α-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene,vinyltoluene, and combinations thereof. Suitable vinyl esters ofcarboxylic acids include vinyl esters of carboxylic acids comprising upto 20 carbon atoms, such as vinyl laurate, vinyl stearate, vinylpropionate, versatic acid vinyl esters, and combinations thereof.Suitable vinyl halides can include ethylenically unsaturated compoundssubstituted by chlorine, fluorine or bromine, such as vinyl chloride andvinylidene chloride. Suitable vinyl ethers can include, for example,vinyl ethers of alcohols comprising 1 to 4 carbon atoms, such as vinylmethyl ether or vinyl isobutyl ether. Aliphatic hydrocarbons having 2 to8 carbon atoms and one or two double bonds can include, for example,hydrocarbons having 2 to 8 carbon atoms and one olefinic double bond,such as ethylene, as well as hydrocarbons having 4 to 8 carbon atoms andtwo olefinic double bonds, such as butadiene, isoprene, and chloroprene.

In some embodiments, the polymer derived from one or moreethylenically-unsaturated monomers comprises a copolymer of ethylene andn-butyl acrylate. In some embodiments, the polymer derived from one ormore ethylenically-unsaturated monomers comprises a copolymer of styreneand one or more of isoprene and butadiene. In certain embodiments, thepolymer derived from one or more ethylenically-unsaturated monomerscomprises a metallocene-catalyzed polyolefin. Examples of suitablemetallocene-catalyzed polyolefins include metallocene polyethylenehomopolymers and metallocene polyethylene copolymers, which arecommercially available, for example, from Exxon Mobil Corporation (underthe trade name EXACT®) and Dow Chemical Company (under the trade nameAFFINITY®).

In certain embodiments, the polymer derived from one or moreethylenically-unsaturated monomers comprises a polymer derived fromvinyl acetate. Polymers derived from vinyl acetate include polymersderived, at least in part, from polymerization of vinyl acetatemonomers. For example, the polymer derived from vinyl acetate can be ahomopolymer of vinyl acetate (i.e., polyvinyl acetate; PVA). The polymerderived from vinyl acetate can also be a copolymer of vinyl acetate andone or more additional ethylenically-unsaturated monomers (e.g.,poly(ethylene-co-vinyl acetate), EVA). In these embodiments, the polymerderived from vinyl acetate can be derived from varying amounts of vinylacetate, so as to provide a polymer having the chemical and physicalproperties suitable for a particular application.

In some embodiments, the polymer derived from vinyl acetate is derivedfrom at least 5% by weight vinyl acetate, based on the total weight ofall of the monomers polymerized to form the polymer (e.g., at least 7.5%by weight, at least 9% by weight, at least 10% by weight, at least 11%by weight, at least 12% by weight, at least 13% by weight, at least 14%by weight, at least 15% by weight, at least 16% by weight, at least 17%by weight, at least 18% by weight, at least 19% by weight, at least 20%by weight, at least 21% by weight, at least 22% by weight, at least 23%by weight, at least 24% by weight, at least 25% by weight, at least 26%by weight, at least 27% by weight, at least 28% by weight, at least 29%by weight, at least 30% by weight, at least 31% by weight, at least 32%by weight, at least 33% by weight, at least 34% by weight, at least 35%by weight, at least 37.5% by weight, at least 40% by weight, at least45% by weight, at least 50% by weight, at least 55% by weight, at least60% by weight, at least 65% by weight, at least 70% by weight, at least75% by weight, at least 80% by weight, at least 85% by weight, or atleast 90% by weight). In some embodiments, the polymer derived fromvinyl acetate is derived from 95% by weight or less vinyl acetate, basedon the total weight of all of the monomers polymerized to form thepolymer (e.g., 90% by weight or less, 85% by weight or less, 80% byweight or less, 75% by weight or less, 70% by weight or less, 65% byweight or less, 60% by weight or less, 55% by weight or less, 50% byweight or less, 45% by weight or less, 40% by weight or less, 37.5% byweight or less, 35% by weight or less, 34% by weight or less, 33% byweight or less, 32% by weight or less, 31% by weight or less, 30% byweight or less, 29% by weight or less, 28% by weight or less, 27% byweight or less, 26% by weight or less, 25% by weight or less, 24% byweight or less, 23% by weight or less, 22% by weight or less, 21% byweight or less, 20% by weight or less, 19% by weight or less, 18% byweight or less, 17% by weight or less, 16% by weight or less, 15% byweight or less, 14% by weight or less, 13% by weight or less, 12% byweight or less, 11% by weight or less, 10% by weight or less, 9% byweight or less, or 7.5% by weight or less).

The polymer derived from vinyl acetate can be a copolymer derived froman amount of vinyl acetate ranging from any of the minimum values aboveto any of the maximum values above. For example, the polymer derivedfrom vinyl acetate can be a copolymer derived from 5% by weight to lessthan 100% by weight vinyl acetate, based on the total weight of all ofthe monomers polymerized to form the polymer (e.g., from 5% by weight to75% by weight vinyl acetate, from 10% by weight to 40% by weight vinylacetate, or from 17% by weight to 34% by weight vinyl acetate).

In the case of copolymers derived from vinyl acetate and one or moreethylenically-unsaturated monomers, any suitableethylenically-unsaturated monomers can be incorporated in the copolymer,so as to provide a copolymer having the chemical and physical propertiesdesired for a particular application. By way of example, suitableethylenically-unsaturated monomers which can be incorporated into thecopolymers include those described above, including (meth)acrylatemonomers, vinyl aromatic monomers (e.g., styrene), vinyl esters of acarboxylic acids, (meth)acrylonitriles, vinyl halides, vinyl ethers,(meth)acrylamides and (meth)acrylamide derivatives, ethylenicallyunsaturated aliphatic monomers (e.g., ethylene, butylene, butadiene),and combinations thereof.

In certain embodiments, the polymer is poly(ethylene-co-vinyl acetate)(EVA). EVA is a copolymer derived from ethylene and vinyl acetate. EVAis widely used in a variety of applications, including as a copolymer inhot-melt adhesives, in road marking and pavement marking applications,in biomedical applications (e.g., as a matrix for controlled drugdelivery), as an additive in plastic films, and as a foam in a varietyof consumer products. Optionally, the EVA copolymer can be grafted withsuitable olefinic monomers, such as butadiene, to obtain copolymershaving the particular chemical and physical properties required for aparticular application. See, for example, U.S. Pat. No. 3,959,410 toDiRossi and U.S. Pat. No. 5,036,129 to Atwell, et al.

In certain embodiments, the polymer is EVA derived from 9% by weight toless than 45% by weight vinyl acetate, based on the total weight of allof the monomers polymerized to form the polymer (e.g., from 17% byweight to 40% by weight vinyl acetate, from 17% by weight to 34% byweight vinyl acetate, or from 25% by weight to 30% by weight vinylacetate) and from greater than 55% by weight to 91% by weight ethylene(e.g., from 60% by weight to 83% by weight vinyl acetate, from 66% byweight to 83% by weight vinyl acetate, or from 70% by weight to 75% byweight vinyl acetate). In one embodiment, the polymer derived from vinylacetate is EVA derived from 26% by weight to 28% by weight vinyl acetateand from 72% by weight to 74% by weight ethylene, based on the totalweight of all of the monomers polymerized to form the polymer.

In some embodiments, the polymer has a melting temperature, as measuredby differential scanning calorimetry (DSC) using the standard methoddescribed in ISO 11357-3:2011, of greater than 25° C. (e.g., greaterthan 30° C., greater than 35° C., greater than 40° C., greater than 45°C., greater than 50° C., greater than 55° C., greater than 60° C.,greater than 65° C., greater than 70° C., greater than 75° C., greaterthan 80° C., or greater than 85° C., greater than 90° C., or greaterthan 95° C.). The polymer derived from vinyl acetate can have a meltingtemperature of less than 100° C. (e.g., less than 95° C., less than 90°C., less than 85° C., less than 80° C., less than 75° C., less than 70°C., less than 65° C., less than 60° C., less than 55° C., less than 50°C., less than 45° C., less than 40° C., less than 35° C., or less than30° C.)

The polymer can have a melting temperature ranging from any of theminimum values above to any of the maximum values above. For example,the polymer can have a melting temperature, as measured by differentialscanning calorimetry (DSC) using the standard method described in ISO11357-3:2011, of from 25° C. to 100° C. (e.g., from 25° C. to 90° C.,from 35° C. to 85° C., or 50° C. to 80° C.).

The rosin ester can be present in the polymeric compositions in varyingamounts, depending upon the desired properties of the composition. Insome embodiments, the rosin ester comprises at least 5% by weight of thecomposition (e.g., at least 10% by weight of the composition, at least15% by weight of the composition, at least 20% by weight of thecomposition, at least 25% by weight of the composition, at least 30% byweight of the composition, at least 35% by weight of the composition, atleast 40% by weight of the composition, or at least 45% by weight of thecomposition). In some embodiments, the rosin ester comprises 50% or lessof the composition by weight (e.g., 45% or less by weight, 40% or lessby weight, 35% or less by weight, 30% or less by weight, 25% or less byweight, 20% or less by weight, 15% or less by weight, or 10% or less byweight). The rosin ester can be present in the composition in an amountranging from any of the minimum values above to any of the maximumvalues above. In some embodiments, rosin ester is present in thecomposition in an amount ranging from 20% to 50% by weight, based on thetotal weight of the composition (e.g., from 30% to 40% by weight).

Similarly, the polymer derived from one or moreethylenically-unsaturated monomers can be present in the polymericcompositions in varying amounts, depending upon the desired propertiesof the composition. In some embodiments, the polymer derived from one ormore ethylenically-unsaturated monomers comprises at least 20% by weightof the composition (e.g., at least 25% by weight of the composition, atleast 30% by weight of the composition, at least 35% by weight of thecomposition, at least 40% by weight of the composition, at least 45% byweight of the composition, at least 50% by weight of the composition, atleast 55% by weight of the composition, at least 60% by weight of thecomposition; at least 65% by weight of the composition, at least 70% byweight of the composition, at least 75% by weight of the composition, atleast 80% by weight of the composition, at least 85% by weight of thecomposition, or at least 90% by weight of the composition). In someembodiments, the polymer derived from one or moreethylenically-unsaturated monomers comprises 95% or less of thecomposition by weight (e.g., 90% or less by weight, 85% or less byweight, 80% or less by weight, 75% or less by weight, 70% or less byweight, 65% or less by weight, 60% or less by weight, 55% or less byweight, 50% or less by weight, 45% or less by weight, 40% or less byweight, 35% or less by weight, 30% or less by weight, 25% or less byweight, 20% or less by weight, 15% or less by weight, or 10% or less byweight). The rosin ester can be present in the composition in an amountranging from any of the minimum values above to any of the maximumvalues above. In some embodiments, the polymer derived from one or moreethylenically-unsaturated monomers is present in the composition in anamount ranging from 20% to 60% by weight, based on the total weight ofthe composition (e.g., from 30% to 40% by weight).

In certain embodiments, the weight ratio of the polymer derived from oneor more ethylenically-unsaturated monomers to the total amount ofesterified dehydroabietic acid and esterified dihydroabietic acid in thecomposition is at least 1:2.2 (e.g., at least 1:2.1, at least 1:2.0, atleast 1:1.9, at least 1:1.8, at least 1:1.7, at least 1:1.6, at least1:1.5, at least 1:1.4, at least 1:1.3, at least 1:1.2, at least 1:1.1,at least 1:1, at least 1.1:1, at least 1.2:1, at least 1.3:1, at least1.4:1, at least 1.5:1, at least 1.6:1, at least 1.7:1, at least 1.8:1,at least 1.9:1, at least 2:1, at least 2.1:1, at least 2.2:1, at least2.3:1, at least 2.4:1, at least 2.5:1, at least 2.6:1, at least 2.7:1,at least 2.8:1, at least 2.9:1, at least 3:1, at least 3.1:1, at least3.2:1, at least 3.3:1, at least 3.4:1, at least 3.5:1, at least 3.6:1,at least 3.7:1, at least 3.8:1, at least 3.9:1, at least 4:1, at least4.1:1, or at least 4.2:1). In certain embodiments, the weight ratio ofthe polymer derived from one or more ethylenically-unsaturated monomersto the total amount of esterified dehydroabietic acid and esterifieddihydroabietic acid in the composition is 4.3:1 or less (e.g., 4.2:1 orless, 4.1:1 or less, 4:1 or less, 3.9:1 or less, 3.8:1 or less, 3.7:1 orless, 3.6:1 or less, 3.5:1 or less, 3.4:1 or less, 3.3:1 or less, 3.2:1or less, 3.1:1 or less, 3:1 or less, 2.9:1 or less, 2.8:1 or less, 2.7:1or less, 2.6:1 or less, 2.5:1 or less, 2.4:1 or less, 2.3:1 or less,2.2:1 or less, 2.1:1 or less, 2:1 or less, 1.9:1 or less, 1.8:1 or less,1.7:1 or less, 1.6:1 or less, 1.5:1 or less, 1.4:1 or less, 1.3:1 orless, 1.2:1 or less, 1.1:1 or less, 1:1 or less, 1:1.1 or less, 1:1.2 orless, 1:1.3 or less, 1:1.4 or less, 1:1.5 or less, 1:1.6 or less, 1:1.7or less, 1:1.8 or less, 1:1.9 or less, 1:2 or less, or 1:2.1 or less).The weight ratio of the polymer derived from one or moreethylenically-unsaturated monomers to the total amount of esterifieddehydroabietic acid and esterified dihydroabietic acid in thecomposition can range from any of the minimum values above to any of themaximum values above. For example, in some embodiments, the weight ratioof the polymer derived from one or more ethylenically-unsaturatedmonomers to the total amount of esterified dehydroabietic acid andesterified dihydroabietic acid in the composition is from 1:2.2 to 4.3:1(e.g., from 1:1.1 to 2:1).

In some cases, the polymeric composition can be an adhesive formulation(e.g., hot-melt adhesive formulation), an ink formulation, a coatingformulation, a rubber formulation, a sealant formulation, an asphaltformulation, or a pavement marking formulation (e.g. a thermoplasticroad marking formulation).

In certain embodiments, the composition is a hot-melt adhesive. In theseembodiments, the rosin ester can function as all or a portion of thetackifier component in a traditional hot-melt adhesive formulation. Thepolymer derived from one or more ethylenically-unsaturated monomers(e.g., a polymer derived from vinyl acetate such as EVA), the rosinester, and one or more additional components, can be present in amountseffective to provide a hot-melt adhesive having the characteristicsrequired for a particular application. For example, the polymer derivedfrom one or more ethylenically-unsaturated monomers (e.g., a polymerderived from vinyl acetate such as EVA), can be from 10% by weight to60% by weight of the hot-melt adhesive composition (e.g., from 20% byweight to 60% by weight of the hot-melt adhesive composition, from 25%by weight to 50% by weight of the hot-melt adhesive composition, or from30% by weight to 40% by weight of the hot-melt adhesive composition).The rosin ester can be from 20% by weight to 50% by weight of thehot-melt adhesive composition (e.g., from 25% by weight to 45% by weightof the hot-melt adhesive composition, or from 30% by weight to 40% byweight of the hot-melt adhesive composition).

The hot-melt adhesive can further include one or more additionalcomponents, including additional tackifiers, waxes, stabilizers (e.g.,antioxidants and UV stabilizers), plasticizers (e.g., benzoates andphthalates), paraffin oils, nucleating agents, optical brighteners,pigments dyes, glitter, biocides, flame retardants, anti-static agents,anti-slip agents, anti-blocking agents, lubricants, and fillers. In someembodiments, the hot-melt adhesive further comprises a wax. Suitablewaxes include paraffin-based waxes and synthetic Fischer-Tropsch waxes.The waxes can be from 10% by weight to 40% by weight of the hot-meltadhesive composition, based on the total weight of the composition(e.g., from 20% by weight to 30% by weight of the hot-melt adhesivecomposition).

In certain embodiments, the composition is a hot-melt adhesive and thepolymer derived from one or more ethylenically-unsaturated monomers isEVA. In certain embodiments, the EVA can be derived from 10% by weightto 40% by weight vinyl acetate, based on the total weight of all of themonomers polymerized to form the EVA (e.g., from 17% by weight to 34% byweight vinyl acetate).

In certain embodiments, the composition is a thermoplastic road markingformulation. The thermoplastic road marking formulation can include from5% by weight to 25% by weight of a rosin ester, based on the totalweight of the thermoplastic road marking formulation (e.g., from 10% byweight to 20% by weight of the thermoplastic road marking formulation).The thermoplastic road marking formulation can further include a polymerderived from one or more ethylenically-unsaturated monomers (e.g., apolymer derived from vinyl acetate such as EVA) which can be, forexample, from 0.1% by weight to 1.5% by weight of the thermoplastic roadmarking formulation. The thermoplastic road marking formulation canfurther include a pigment (e.g., from 1% by weight to 10% by weighttitanium dioxide), and glass beads (e.g., from 30% by weight to 40% byweight), and a filler calcium carbonate which can make up the balance ofthe composition up to 100% by weight). The thermoplastic road markingformulation can further include an oil (e.g., from 1% by weight to 5% byweight percent mineral oil), a wax (e.g., from 1% by weight to 5% byweight percent paraffin-based wax or synthetic Fischer-Tropsch wax), astabilizer (e.g., from 0.1% by weight to 0.5% by weight stearic acid),and, optionally, additional polymers and/or binders other than the rosinester described herein.

In some embodiments, by incorporating a rosin ester described hereininto the polymeric composition, the polymeric composition can exhibitimproved thermal stability, including improved viscosity stability onaging at elevated temperatures (thermal aging), improved color stabilityon thermal aging, or combinations thereof.

In some embodiments, the polymeric compositions provided herein exhibitless than a 10% change in viscosity upon incubation at 177° C. for 96hours, when analyzed using the modified ASTM D4499-07 method describedbelow (e.g., less than a 9% change in viscosity, less than an 8% changein viscosity, less than a 7.5% change in viscosity, less than a 7%change in viscosity, less than a 6% change in viscosity, less than a 5%change in viscosity, less than a 4% change in viscosity, less than a 3%change in viscosity, less than a 2.5% change in viscosity, less than a2% change in viscosity, or less than a 1% change in viscosity). In someembodiments, the composition exhibits substantially no change inviscosity (i.e., less than a 0.5% change in viscosity) upon incubationat 177° C. for 96 hours.

In some embodiments, the polymeric compositions provided herein exhibitcolor stability upon thermal aging. In certain cases, the polymericcompositions provided herein exhibit a change of 5 or less Gardner colorunits when heated to a temperature of 177° C. for a period of 96 hours(e.g., 4.5 or less, 4.0 or less, 3.5 or less, 3.0 or less, 2.5 or less,2.0 or less, 1.5 or less, 1.0 or less, or 0.5 or less).

The polymeric compositions provided herein can be used in a variety ofapplications, including as adhesives (e.g., hot-melt adhesives), inks,coatings, rubbers, sealants, asphalt, and thermoplastic road markingsand pavement markings. In some embodiments, the compositions arehot-melt adhesives used, for example, in conjunction with papers andpackaging (e.g., to adhere surfaces of corrugated fiberboard boxes andpaperboard cartons during assembly and/or packaging, to prepareself-adhesive labels, to apply labels to packaging, or in otherapplications such as bookbinding), in conjunction with non-wovenmaterials (e.g., to adhere nonwoven material with a backsheet during theconstruction of disposable diapers), in adhesive tapes, in apparel(e.g., in the assembly of footware, or in the assembly of multi-wall andspecialty handbags), in electrical and electronic bonding (e.g., toaffix parts or wires in electronic devices), in general wood assembly(e.g., in furniture assembly, or in the assembly of doors and millwork), and in other industrial assembly (e.g., in the assembly ofappliances). The rosin esters described herein can also be used in avariety of additional applications, including as a softener andplasticizer in chewing gum bases, as a weighting and clouding agent inbeverages (e.g., citrus flavored beverages), as a surfactant, surfaceactivity modulator, or dispersing agent, as an additive in waxes andwax-based polishes, as a modifier in cosmetic formulations (e.g.,mascara), and as a curing agent in concrete.

Also provided are compositions comprising a rosin ester described hereinand an oil. Exemplary compositions can include 25% by weight to 55% byweight (e.g., 30% by weight to 50% by weight) of a rosin ester describedherein and 45% by weight to 75% by weight (e.g., 50% by weight to 70% byweight) of an oil, such as mineral oil or poly-butene oil.

Also provided are methods of making the rosin esters described herein.Methods of making rosin esters can comprise (a) esterifying a rosin withan alcohol to provide a crude rosin ester composition, and (b)hydrogenating the crude rosin ester composition to form the rosin ester.

Esterification step (a) can comprise contacting a rosin with a suitablealcohol, and allowing the rosin and the alcohol to react for a period oftime and under suitable conditions to form the crude rosin ester.Methods of esterifying rosin are known in the art. See, for example,U.S. Pat. No. 5,504,152 to Douglas et al., which is hereby incorporatedby reference in its entirety. Suitable methods for esterifying rosin canbe selected in view of a number of factors, including the nature of thereactants (e.g., the chemical and physical properties of the rosin, theidentity of the alcohol, etc.) and the desired chemical and physicalproperties of the resultant rosin ester. For example, rosin can beesterified by a thermal reaction of the rosin with an alcohol.Esterification can comprise contacting the rosin with the alcohol at anelevated temperature (e.g., at a temperature from greater than greaterthan 30° C. to 250° C.). In some embodiments, esterification step (a)can involve contacting molten rosin with an alcohol and optionally anesterification catalyst for a period of time suitable to form the cruderosin ester. In some cases, the esterification reaction involvescontacting the rosin with an alcohol and optionally an esterificationcatalyst for a period of time effective to provide a rosin ester havingan acid number of 15 or less.

Any suitable rosin can be used in esterification step (a). The rosin canbe a tall oil rosin, a gum rosin, a wood rosin, or a combinationsthereof. In certain embodiments, the rosin comprises tall oil rosin.Rosins can be used as a feedstock for the formation of rosin esters asobtained from a commercial or natural source. Examples of commerciallyavailable rosins include tall oil rosins such as SYLVAROS® 90,commercially available from Arizona Chemical. Alternatively, rosin canbe subjected to one or more purification steps (e.g., distillation underreduced pressure, extraction, and/or crystallization) prior to its useas a feedstock for the formation of rosin esters.

Any suitable alcohol, include monoalcohols, diols, and other polyols,can be used in esterification step (a). Examples of suitable alcoholsinclude glycerol, pentaerythritol, dipentaerythritol, ethylene glycol,diethylene glycol, triethylene glycol, sorbitol, neopentylglycol,trimethylolpropane, methanol, ethanol, propanol, butanol, amyl alcohol,2-ethyl hexanol, diglycerol, tripentaerythritol, C₈-C₁₁ branched orunbranched alkyl alcohols, and C₇-C₁₆ branched or unbranchedarylalkylalcohols. In certain embodiments, the alcohol is a polyhydricalcohol selected from the group consisting of ethylene glycol, propyleneglycol, diethylene glycol, triethylene glycol, tetraethylene glycol,trimethylene glycol, glycerol, trimethylolpropane, trimethylolethane,pentaerythritol, mannitol, and combinations thereof. In someembodiments, more than one alcohol is used in esterification step (a).In certain embodiments, pentaerythritol and one or more additionalalcohols selected from the group consisting of glycerol,dipentaerythritol, ethylene glycol, diethylene glycol, triethyleneglycol, trimethylolpropane, and combinations thereof are used inesterification step (a).

The amount of alcohol employed in esterification step (a) relative tothe amount of rosin can be varied, depending on the nature of thealcohol and the desired chemical and physical properties of theresultant rosin ester. In some embodiments, the rosin is provided inexcess so as to produce a resultant rosin ester having a low hydroxylnumber. For example, the alcohol can be provided in an amount such thatless than a molar equivalent of hydroxy groups is present in thereaction relative to the amount of rosin present. In other embodiments,the alcohol is provided in excess so as to produce a resultant rosinester having a low acid number.

As is known in the art, catalysts, solvents, bleaching agents,stabilizers, and/or antioxidants can be added in esterification step(a). Suitable catalysts, solvents, bleaching agents, stabilizers, andantioxidants are known in the art, and described, for example, in U.S.Pat. Nos. 2,729,660, 3,310,575, 3,423,389, 3,780,013, 4,172,070,4,548,746, 4,690,783, 4,693,847, 4,725,384, 4,744,925, 4,788,009,5,021,548, and 5,049,652. In order to drive the esterification reactionto completion, water can be removed from the reactor using standardmethods, such as distillation and/or application of a vacuum.

Hydrogenation step (b) can comprise contacting the crude rosin esterwith a hydrogenation catalyst. Methods of hydrogenating rosin esters areknown in the art. Hydrogenation reactions can be carried out using acatalyst, such as a heterogeneous hydrogenation catalyst (e.g., apalladium catalyst, such as Pd supported on carbon (Pd/C), a platinumcatalyst, such as PtO₂, a nickel catalyst, such as Raney Nickel (Ra—Ni),a rhodium catalyst, or a ruthenium catalyst). In some cases, thehydrogenation catalyst can be present in an amount ranging from 0.25% to5% by weight, based on the total weight of the crude rosin ester. Thehydrogen source for the hydrogenation can by hydrogen (H₂) or a compoundwhich can generate hydrogen under reaction conditions, such as formicacid, isopropanol, cyclohexene, cyclohexadiene, a diimide, or hydrazine.

Step (b) can be performed at an elevated temperature, an elevatedpressure, or combinations thereof. For example, step (b) is performed ata temperature ranging from 150° C. to 300° C. (e.g., from 180° C. to280° C., from 180° C. to 240° C., from 200° C. to 280° C. or from 220°C. to 260° C.). Step (b) can performed at a pressure ranging from 250 to2000 psi (e.g., from 250 to 1450 psi, from 250 to 650 psi, or from 350to 550 psi).

Optionally a solvent can be present in esterification step (a),hydrogenation step (b), or combinations thereof. In certain embodiments,the rosin esterified in step (a) and/or the crude rosin estercomposition hydrogenated in step (b) comprise less than 25% by weightsolvent. In some embodiments, the concentration of esterified rosinacids in the crude rosin ester composition hydrogenated in step (b) is75% or more by weight, based on the total weight of the crude rosinester composition. In some embodiments, the crude rosin estercomposition is substantially free of solvent (e.g., the crude rosinester composition comprises less than by weight solvent, based on thetotal weight of the crude rosin ester composition). In certainembodiments, the crude rosin ester composition hydrogenated in step (h)has a viscosity of 1,000 cP or less at 25° C.

In some embodiments, the crude rosin ester composition obtained fromesterification step (a) is hydrogenated in step (b) without anintervening distillation step. In certain embodiments, the crude rosinester composition obtained from esterification hydrogenated in step (b)without any intervening purification step. For example, the crude rosinester composition obtained from esterification step (a) can be directlyhydrogenated in step (b).

In some cases, methods of making the rosin esters described hereininclude only a single hydrogenation step. In some embodiments, methodsof making the rosin esters described herein consist essentially ofesterifying step (a) and hydrogenating step (b). In such cases, themethods involve no additional processing steps which influence theweight ratio of esterified dehydroabietic acid to esterifieddihydroabietic acid in the rosin ester, such as dehydrogenation,hydrogenation of the rosin prior to esterification (i.e.,pre-hydrogenation), disproportionation of the rosin prior toesterification (i.e., pre-disproportionation), distillation, the use ofadditional/alternative catalysts, or combinations thereof. In certainembodiments, methods of making the rosin esters described herein consistof esterifying step (a) and hydrogenating step (b).

To obtain a rosin ester having the desired chemical and physicalproperties for particular applications, methods of making the rosinesters described herein can optionally further include one or moreadditional processing steps in addition to esterifying step (a) andhydrogenating step (b). In some embodiments, the rosin to be esterifiedin step (a), the crude rosin ester, and/or the rosin ester can befurther processed, for example, to decrease the PAN number of the rosin,crude rosin ester, and/or rosin ester; to influence the weight ratio ofvarious rosin acids and/or rosin acid esters present in the rosin, cruderosin ester, and/or rosin ester; to influence the hydroxyl number of theresultant rosin ester; to influence the acid number of the resultantrosin ester; or combinations thereof. Suitable additional processingsteps are known in the art, and can include additional hydrogenationsteps, dehydrogenation, disproportionation, dimerization, andfortification. In certain embodiments, rosin is processed using one ormore of these methods prior to esterifying step (a) to improve thechemical and physical properties of the resultant rosin esters. Wherechemically permissible, such methods can also be performed incombination with esterifying step (a), following esterifying step (a)but prior to hydrogenating step (b), following hydrogenating step (b),or combinations thereof to obtain a rosin ester having the desiredchemical and physical properties, as discussed in more detail below.

In certain embodiments, the methods of making rosin esters can furthercomprise disproportionating the rosin prior to the esterifying step (a).Rosin disproportionation converts abietadienoic acid moieties intodehydroabietic acid and dihydroabietic acid moieties. Methods ofdisproportionation are known in the art, and can involve heating rosin,often in the presence of one or more disproportionation agents. Suitablemethods for disproportionating rosin are described in, for example, U.S.Pat. Nos. 3,423,389, 4,302,371, and 4,657,703, all of which areincorporated herein by reference.

A variety of suitable disproportionation agents can be used. Examples ofsuitable disproportionation agents include thiobisnaphthols, including2,2′thiobisphenols, 3,3′-thiobisphenols, 4,4′-thiobis(resorcinol) andt,t′-thiobis(pyrogallol), 4,4′-15 thiobis(6-t-butyl-m-cresol) and4/4′-thiobis(6-t-butyl-o-cresol) thiobisnaphthols, 2,2′-thio-bisphenols,3,3′-thio-bis phenols; metals, including palladium, nickel, andplatinum; iodine or iodides (e.g., iron iodide); sulfides (e.g., ironsulfide); and combinations thereof. In certain embodiments, the rosin isdisproportionate using a phenol sulfide type disproportionation agent.Examples of suitable phenol sulfide type disproportionation agentsinclude poly-t-butylphenoldisulfide (commercially available under thetrade name ROSINOX® from Arkema, Inc.),4,4′thiobis(2-t-butyl-5-methylphenol (commercially available under thetrade name LOWINOX® TBM-6 from Chemtura), nonylphenol disulfideoligomers (such as those commercially available under the trade nameETHANOX® TM323 from Albemarle Corp.), and amylphenol disulfide polymer(such as those commercially available under the trade name VULTAC® 2from Sovereign Chemical Co.).

In certain embodiments, the rosin is disproportionated prior toesterifying step (a). In these embodiments, a disproportionated rosin orpartly disproportionated rosin can be used as a feedstock foresterifying step (a). In some cases, disproportionation or furtherdisproportionation can be conducted during esterifying step (a). Forexample, disproportionated or partly disproportionated rosin can begenerated in situ and esterified thereafter in a one-pot synthesisprocedure to a rosin ester.

Optionally, the rosin, crude rosin ester, and/or rosin ester can befortified to improve the chemical and physical properties of theresultant rosin esters. In some embodiments, rosin is fortified prior toesterifying step (a) to improve the chemical and physical properties ofthe resultant rosin esters. Fortification of rosin involves the chemicalmodification of the conjugated double bond system of rosin acids in therosin, so as to provide a rosin having a lower PAN number and highermolecular weight than the rosin prior to fortification. A number ofsuitable chemical modifications and related chemical methods are knownin the art. For example, rosins can be fortified by means of aDiels-Alder or Ene addition reaction of a rosin acid with a dienophile,such as an α,β-unsaturated organic acid or the anhydride of such anacid. Examples of suitable dienophiles include maleic acid, fumaricacid, acrylic acid, esters derived from these acids, and maleicanhydride.

Optionally, methods can include one or more process steps to influencethe hydroxyl number of the resultant rosin ester, to influence the acidnumber of the resultant rosin ester; or combinations thereof. Ifdesired, rosin esters can be chemically modified followingesterification (e.g., following esterifying step (a) but prior tohydrogenating step (b) or following hydrogenating step (b)) to provide arosin ester having a low hydroxyl number. This process can involvechemical modification of residual hydroxyl moieties in the crude rosinester or rosin esters following esterification using synthetic methodsknown in the art. For example, the crude rosin ester or rosin ester canbe reacted with an acylating agent (e.g., a carboxylic acid or aderivative thereof, such as an acid anhydride). See, for example, U.S.Pat. No. 4,380,513 to Ruckel. Residual hydroxyl moieties in the cruderosin ester or rosin ester can also be reacted with an electrophilicreagent, such as an isocyanate, to produce the corresponding carbamatederivative. See, for example, U.S. Pat. No. 4,377,510 to Ruckel. Othersuitable electrophilic reagents which can be used to react residualhydroxyl moieties include alkylating agents (e.g., methylating agentssuch as dimethylsulphate). If desired, following esterification (e.g.,following esterifying step (a) but prior to hydrogenating step (b) orfollowing hydrogenating step (b)), unreacted rosin as well as othervolatile components, can be removed from the crude rosin ester or rosinester, for example, by steam sparging, sparging by an inert gas such asnitrogen gas, wiped film evaporation, short path evaporation, and vacuumdistillation. By stripping excess rosin (i.e., rosin acids) from thecrude rosin ester or rosin ester, the acid number of the resultant rosinester can be reduced.

Also provided are methods for preparing polymer compositions, includinghot-melt adhesives. Methods for preparing polymer compositions caninclude mixing a polymer derived from vinyl acetate and a rosin ester asdescribed herein (e.g., a rosin ester comprising at least 70% by weightof an esterified dehydroabietic acid and an esterified dihydroabieticacid, wherein the weight ratio of the esterified dehydroabietic acid tothe esterified dihydroabietic acid ranges from 1.3:1 to 1:2.6). Methodscan further include adding one or more additional components to thecomposition, such as an additional tackifier, a wax, a stabilizer (e.g.,an antioxidant UV stabilizer), a plasticizer (e.g., benzoates,phthalates), paraffin oil, a nucleating agent, an optical brightener, apigment, a dye, glitter, a biocide, a flame retardant, an anti-staticagent, an anti-slip agent, an anti-blocking agent, a lubricants, afiller, or a combination thereof. Methods can further include preparinga rosin ester (e.g., a rosin ester comprising at least 70% by weight ofan esterified dehydroabietic acid and an esterified dihydroabietic acid,wherein the weight ratio of the esterified dehydroabietic acid to theesterified dihydroabietic acid ranges from 1.3:1 to 1:2.6) using themethods described herein.

An exemplary road marking formulation may be prepared by: (a) charging astandard mixer with 16 parts rosin ester, 2.8 parts oil (e.g., a mineraloil, such as mineral oil; obtained from Statoil), 1 part wax (e.g.,polyethylene wax, such as AC6 PE-wax obtained from Honeywell), 1 part ofa polymer derived from vinyl acetate (e.g., poly(ethylene-co-vinylacetate) such as Elvax 22W obtained from DuPont), 0.2 parts fatty acid(e.g., stearic acid), 5.3 parts pigment (e.g., titanium dioxide, such astitanium dioxide obtained from Kronos), 42.4 parts filler (e.g., calciumcarbonate), and 37.1 parts reflective filler (e.g., glass beads, such asglass beads obtained from Swarco); and (b) heating (e.g., at 180° C.)and blending at low speed to avoid introducing air bubbles into themelt.

By way of non-limiting illustration, examples of certain embodiments ofthe present disclosure are included below.

EXAMPLES

General Methods

All materials were characterized using the following methods unlessotherwise stated. Hydroxyl numbers were determined according to amodified method (different solvent tetrahydrofuran was applied) of DIN53240-2 entitled “Determination of Hydroxyl Value—Part 2: Method withCatalyst,” which is incorporated herein by reference in its entirety.The rosin ester (dissolved in tetrahydrofuran) was reacted with aceticanhydride in the presence of 4-dimethylaminopyridine (DMAP). Residualacetic anhydride was hydrolyzed and the resulting mixture titrated withan alcoholic solution of potassium hydroxide (0.5 M). The hydroxylnumber is expressed as mg KOH per gram rosin ester sample. Acid numberswere determined according to method described in ASTM D465-05 (2010)entitled “Standard Test Methods for Acid Number of Naval Stores ProductsIncluding Tall Oil and Other Related Products,” which is incorporatedherein by reference in its entirety. The acid number is expressed as mgKOH per gram rosin ester sample. Softening points were determinedaccording to method described in ASTM E28-99 (2009) entitled “StandardTest Methods for Softening Point of Resins Derived from Naval Stores byRing-and-Ball Apparatus,” which is incorporated herein by reference inits entirety. The Gardner color of all materials was measured accordingto the Gardner Color scale as specified in ASTM D1544-04 (2010) entitled“Standard Test Method for Color of Transparent Liquids (Gardner ColorScale),” which is incorporated herein by reference in its entirety.Gardner colors were measured using a Dr Lange LICO® 200 colorimeter.Unless otherwise indicated, all Gardner colors were measured using neatsamples. Oxidative-induction time was measured according to the standardmethods specified in ASTM D5483-05(2010) entitled “Standard Test Methodfor Oxidation Induction Time of Lubricating Greases by PressureDifferential Scanning Calorimetry,” which is incorporated herein byreference in its entirety. Unless otherwise specified, theoxidative-induction time was measured at 130° C. using 550 psi ofoxygen. Sulfur content was measured according to the standard methodsdescribed in ASTM D5453-05 entitled “Standard Test Method forDetermination of Total Sulfur in Light Hydrocarbons, Motor Fuels andOils by Ultraviolet Fluorescence,” which is incorporated herein byreference in its entirety. Sulfur content was measured using an ANTEK®9000 sulfur analyzer.

The isomeric composition of the rosin esters, including the PAN numberand the ratio of esterified dehydroabietic acid to esterifieddihydroabietic acid, was determined according to the methods describedin ASTM D5974-00 (2010) entitled “Standard Test Methods for Fatty andRosin Acids in Tall Oil Fractionation Products by Capillary GasChromatography,” which is incorporated herein by reference in itsentirety. Specifically, a rosin ester sample (1.00 g) and 10 mL 2Npotassium hydroxide (KOH) in ethanol were added to a high pressuremicrowave reaction vessel. The reaction vessel was sealed and placedinto the rotor of a Perkin Elmer MULTIWAVE® 3000 Microwave System. Thesample was saponified in the microwave for 30 minutes at 150° C. Uponcompletion of the microwave-assisted saponification, the reactionmixture was transferred to a separatory funnel, and dilute hydrochloricacid was added to reduce the pH value to less than 4. This converted therosin soaps in the reaction mixture to rosin acids. The resulting rosinacids were isolated by way of ethyl ether extraction. Upon removal ofthe ether solvent, the rosin acids were derivatized and analyzed using agas chromatograph according to ASTM D5974-00 (2010).

Preparation of Rosin Esters

Example 1

500 g of tall oil rosin (SYLVAROS® HYR, commercially available fromArizona Chemical) with a Gardner color (neat) of 5.5 and an acid numberof 180.7 was charged into a four-necked flask (2 L) and heated to 200°C. under a nitrogen atmosphere. After the rosin was completely melted,the rosin was agitated, and pentaerythritol (57.4 g) and IRGANOX® 1425(1.98 g) were added. The reaction mixture was heated to 275° C. (heatingrate of 30° C./hour) and left at this temperature for 7.5 hours. Thecrude rosin ester was discharged, and analyzed to have a with a Gardnercolor (neat) of 5.6, an acid number of 13.8, softening point of 97.1°C., and an oxidative-induction time of 0.5 minutes.

Without further purification, the crude rosin ester was hydrogenated for6 hours at 650 psi and 260° C. using 2% by weight palladium on carbon(5% Pd by weight). The catalyst was then removed by filtration,providing a rosin ester with a Gardner color (neat) of 1.4, an acidnumber of 11.2, softening point of 98.0° C., and an oxidative-inductiontime of 39.6 minutes. The color stability of the rosin ester was alsotested. After incubation for three hours at 160° C., the rosin esterexhibited a Gardner color (neat) of 1.4. The weight ratio of esterifieddehydroabietic acid to esterified dihydroabietic acid in the resultingrosin ester was determined to be 1:1.6.

Example 2

The procedure of Example 1 was repeated, except that a solvent was addedduring the hydrogenation reaction.

The crude rosin ester was prepared as described in Example 1. Withoutfurther purification, the crude rosin ester was hydrogenated for 6 hoursat 650 psi and 260° C. using 2% by weight palladium on carbon (5% Pd byweight) in a 50% by weight solution of dimethylcyclohexane. The catalystwas then removed by filtration, and the solvent was removed bydistillation. The resulting rosin ester exhibited a Gardner color (neat)of 0.8, an acid number of 11.4, softening point of 97.4° C., a PANnumber of 0, and an oxidative-induction time of 43.0 minutes. The colorstability of the rosin ester was also tested. After incubation for threehours at 160° C., the rosin ester exhibited a Gardner color (neat) of0.8. The weight ratio of esterified dehydroabietic acid to esterifieddihydroabietic acid in the resulting rosin ester was determined to be1:1.6.

Example 3

500 g of tall oil rosin was charged into a four-necked flask (1 L). Theflask was placed under vacuum for 10-15 minutes. The vacuum was thenbroken with nitrogen, and the flask was heated to 180° C. and agitated.ROSINOX® (poly-t-butylphenoldisulfide 1.74 g, 0.31 wt %, commerciallyavailable from Arkema, Inc) was added to the reaction flask. Thereaction flask contents were then stirred for 5-10 minutes. A catalyst(calcium-bis(((3,5-bis(1,1-dimethylethyl)-4-hydroxyphenyl)methyl)-ethylphosphonate),1.98 g) and pentaerytritol (57.4 g) were added, and the reaction washeated to 270° C. at a rate of 35° C. per hour. The reaction temperaturewas maintained at 275° C. until the acid number of the mixture was lessthan 15. The crude rosin ester was discharged.

Without further purification the crude rosin ester was hydrogenated for6 hours at 450 psi and 260° C. using 1.5% by weight palladium on carbon(5% Pd by weight). The catalyst was then removed by filtration intoluene, and the solvent was removed by distillation. The resultingrosin ester exhibited a Gardner color (neat) of 2.3, an acid number of10, softening point of 96° C., and an oxidative-induction time of 44.4minutes. The weight ratio of esterified dehydroabietic acid toesterified dihydroabietic acid in the resulting rosin ester wasdetermined to be 1.01:1.

Formulation of Hot-Melt Adhesives

Hot-melt adhesives were formulated using the rosin esters prepared inExamples 1 and 2. The hot-melt adhesive compositions were prepared byblending 20 wt % ESCORENE® Ultra UL 7711 EVA (EVA copolymer with a 26.7wt % vinyl acetate content, commercially available from Exxon MobilChemical), 16.4 wt % ELVAX® EVA (EVA copolymer with a 28 wt % vinylacetate content, commercially available from DuPont), 25 wt % SASOLWAX®H1 (unmodified Fischer-Tropsch was commercially available fromSasolwax), 38 wt % tackifier (rosin ester), and 0.6% ANOX® 20(3,5-bis(1,1-dimethylethyl)-4-hydroxy-benzenepropanoic acid, stericallyhindered phenolic antioxidant commercially available from GulfStabilizers Industries). For comparison, hot melt adhesives were alsoprepared using SYLVAPACK® RE 100RC (tall oil rosin ester with a Gardnercolor (neat) of 4, an acid number of 11, softening point of 93-100° C.,and a weight ratio of esterified dehydroabietic acid to esterifieddihydroabietic acid of 1:0.4; commercially available from ArizonaChemical) and SYLVALITE® RE 105XL (tall oil rosin ester with a Gardnercolor (neat) of 4, an acid number of 2, softening point of 102° C., anda weight ratio of esterified dehydroabietic acid to esterifieddihydroabietic acid in the resulting rosin ester was determined to be1:0.3; commercially available from Arizona Chemical).

The thermal stability of the hot-melt adhesive formulations was measuredusing a thermal stability test adapted from the test methods describedin ASTM D4499-07, entitled “Standard Test Method for Heat Stability ofHot-Melt Adhesives,” which is incorporated by reference in its entirety.The viscosity of the hot-melt adhesives was measured using a Brookfieldviscometer equipped with a #27 spindle at 133° C. and 177° C. Theviscosity is measured in centipoise (cP).

The viscosity of each composition was measured at 0 hours, 48 hours, and96 hours. The neat Gardner color of each composition was also measuredat 0 hours, 24 hours, 48 hours, 72 hours, and 96 hours. The results areshown in Table 1 below.

TABLE 1 Performance of Hot-Melt Adhesive Formulations Containing RosinEsters Time Garnder Viscosity Δ Tackifer (hours) Color (neat) Δ Color¹(cP)² Viscosity³ Example 1 0 1.5 985 24 3 48 4 992 72 5 96 6.5 5 10082.3% Example 2 0 1.5 1025 24 2 48 3.5 1010 72 4.5 96 5.5 4 1020 0.5% RE100RC 0 3.5 1082 24 5 48 5.5 1092 72 N/A 96 8 4.5 1258 16.0% RE 105XL 02.5 1092 24 4.5 48 6 952 72 N/A 96 9.5 7 998 8.6% ¹Δ Color denotes thedifference between the intial Gardner color of the composition (measuredat 0 hours) and the final Gardner color of the composition (measured at96 hours) measured according to the method described in ASTM D1544-04(2010). ²Viscosity measured at 177° C. using a Brookfield viscometerequipped with a #27 spindle ³Δ Viscosity denotes the percent differencebetween the initial viscosity of the composition (measured at 0 hours)and the final viscosity of the composition (measured at 96 hours)measured according to the method described in ASTM 4499-07.

The compositions and methods of the appended claims are not limited inscope by the specific compositions and methods described herein, whichare intended as illustrations of a few aspects of the claims. Anycompositions and methods that are functionally equivalent are intendedto fall within the scope of the claims. Various modifications of thecompositions and methods in addition to those shown and described hereinare intended to fall within the scope of the appended claims. Further,while only certain representative compositions and method stepsdisclosed herein are specifically described, other combinations of thecompositions and method steps also are intended to fall within the scopeof the appended claims, even if not specifically recited. Thus, acombination of steps, elements, components, or constituents may beexplicitly mentioned herein or less, however, other combinations ofsteps, elements, components, and constituents are included, even thoughnot explicitly stated.

The term “comprising” and variations thereof as used herein is usedsynonymously with the term “including” and variations thereof and areopen, non-limiting terms. Although the terms “comprising” and“including” have been used herein to describe various embodiments, theterms “consisting essentially of” and “consisting of” can be used inplace of “comprising” and “including” to provide for more specificembodiments of the invention and are also disclosed. Other than wherenoted, all numbers expressing geometries, dimensions, and so forth usedin the specification and claims are to be understood at the very least,and not as an attempt to limit the application of the doctrine ofequivalents to the scope of the claims, to be construed in light of thenumber of significant digits and ordinary rounding approaches.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of skill in the artto which the disclosed invention belongs. Publications cited herein andthe materials for which they are cited are specifically incorporated byreference.

What is claimed is:
 1. A rosin ester comprising at least 70% by weightof an esterified dehydroabietic acid and an esterified dihydroabieticacid, wherein the weight ratio of the esterified dehydroabietic acid tothe esterified dihydroabietic acid ranges from 1.3:1 to 1:2.6, whereinthe rosin ester has a weight average molecular weight of at least 800g/mol as determined using gel permeation chromatography as described inATSM D5296-05.
 2. The rosin ester of claim 1, wherein the rosin ester isderived from tall oil rosin, gum rosin, wood rosin, or a combinationthereof.
 3. A composition comprising (a) a polymer derived from one ormore ethylenically-unsaturated monomers, or a blend of two or morepolymers derived from one or more ethylenically-unsaturated monomers,and (b) a rosin ester defined by claim
 1. 4. A method of making a rosinester comprising: (a) esterifying a rosin with an alcohol to provide acrude rosin ester, and (b) hydrogenating the crude rosin ester to formthe rosin ester, wherein the rosin ester has a weight average molecularweight of at least 800 g/mol as determined using gel permeationchromatography as described in ATSM D5296-05.
 5. A compositioncomprising (a) 45% by weight to 75% by weight of an oil, and (b) 25% byweight to 55% by weight of a rosin ester defined by claim
 1. 6. Acomposition comprising a rosin ester, the rosin ester comprising atleast 70% by weight of an esterified dehydroabietic acid and anesterified dihydroabietic acid, wherein the weight ratio of theesterified dehydroabietic acid to the esterified dihydroabietic acidranges from 1.3:1 to 1:2.6 and wherein the rosin ester has a weightaverage molecular weight of at least 800 g/mol as determined using gelpermeation chromatography as described in ATSM D5296-05.